1. Field of the Invention
The present invention relates generally to image forming apparatuses, image processing methods, and computer-readable recording media.
2. Description of the Related Art
With regard to electrophotographic image forming apparatuses, importance is placed on consistency in color of output images. The term “consistency” used herein indicates that each image is output in conformance with designated density and area percentage. If an output image greatly differs in density from input image data, the image is assumed to be defective. For this reason, a technique of correcting information representing an image to be output using data obtained by measuring an output image has been devised.
A method of correcting a light amount and information representing an image to be output using density information obtained from a formed sample image is disclosed in Japanese Laid-open Patent Application No. 2011-257709. Specifically, the method includes forming a sample image of a predetermined density range, measuring densities of the image, and calculating correction information from density information, i.e., the measured densities, in the main-scanning direction.
However, a study carried out by inventors of the present invention indicates that the conventional method of performing correction using only information obtained from an output image of a single color can cause, when the correction is applied to a mixed color, a streak, which does not appear when the correction is applied to a single color, resulting from density nonuniformity to appear, which is disadvantageous.
Therefore, there is a need for an electrophotographic image forming apparatus configured to reduce an image defect resulting from density nonuniformity of single-color and, furthermore, reduce an image defect resulting from density nonuniformity of mixed-color caused by the reduction of the density nonuniformity of single-color.
It is an object of the present invention to at least partially solve the problem in the conventional technology.